Each of the following terms has some anatomical significance. What do these terms mean? Explain with the help of line diagrams.
$(A)$ Plasmodesmata
$(B)$ Middle lamella
$(C)$ Secondary wall

(N/A) Plasmodesmata:
$\Rightarrow$ Structure: These are narrow channels that traverse the cell walls of plant cells and some algal cells,enabling transport and communication between them.
Function: They facilitate the movement of molecules between adjacent plant cells through the symplastic pathway.
$(B)$ Middle lamella:
$\Rightarrow$ Structure: It is a thin,cementing layer located between the primary walls of adjacent cells. It is primarily composed of calcium and magnesium pectates.
Function: It acts as a glue,holding adjacent plant cells together.
$(C)$ Secondary wall:
$\Rightarrow$ Structure: It is a thick,rigid layer formed inside the primary cell wall once the cell has stopped growing. It is composed of cellulose,hemicellulose,and often lignin.
Function: It provides mechanical strength and structural support to the plant cell.